Jokulmorder is a rare Creature — Leviathan card from Coldsnap (CSP), collector number 37. Current market price: $0.60 (foil $4.16), TCGplayer market prices via Scryfall.
Trample This creature enters tapped. When this creature enters, sacrifice it unless you sacrifice five lands. This creature doesn't untap during your untap step. Whenever you play an Island, you may untap this creature.